| The key of the structural design theory is the capability of multi-span greenhouse structures to resist wind. A great deal of studies on the wind load has been done. Little of these studies were aimed at the capability of structure to resist wind. The key issues of the structural design theory with emphasis on the performance of multi-span greenhouse in wind were researched in this paper.The deadweight of multi-span greenhouse is small, but the loads of wind and snow are big. For the first time, aim at these characteristics of multi-span greenhouse; the values of load coefficient in multi-coefficient expression design theory of multi-span greenhouse structure were studied in this paper. The design measure based on aim reliability indexes was introduced to the multi-span greenhouse structure. Mode of fail, function of limit state, probability former and Stat parameter of loads in vary period of time were researched. The conclusion was educed. Effects of wind load and of snow load are larger than those of deadweight, and that was leaded the practicality reliability indexes of the members of multi-span greenhouse structure those designed with the design measure of multi-coefficient expression were less than that of those designed with the design measure based on aim reliability indexes. And the more effects of wind load and of snow load, the little practicality reliability indexes. It was prove that adjustment of these load coefficients was needed to keep the practicality reliability indexes of the members of multi-span greenhouse structure. The accommodation coefficient of varies loads with varies effect ratio was acquired in this paper, and was given in the graphs in this paper.The theory of reliability of structure system was applied to multi-span greenhouse structure system, as example, the system reliability of the NJ-6 type multi-span greenhouse structure was studied. For the first time, mathematics model of system reliability of multi-span greenhouse structure was se up, and the system reliability of the NJ-6 type multi-span greenhouse structure was calculated. It is showed that the failure probability of the NJ-6 type multi-span greenhouse structure is 5.1 X 10-3. It is also showed that the failure probabilities of the most structure members are much less than this value. The failure probability of structure system lies on that of these members whose failure probabilities are much bigger than the other's. Enhancement these members can reduce the failure probability of structure system efficiently.For the time, using commerce software-CFX, wind pressure distributing on the surface of the NJ-6 type multi-span greenhouse was numerical simulated. The disciplinarian of wind pressure was investigated and was found out. Introducing un-dimension parameter, the result dates were processed to wind pressure coefficient. Based on The disciplinarian of wind pressure distributing, the surface of the NJ-6 type multi-span greenhouse was partitioned in several subsections. The weighed integrals of wind pressure coefficient in each subsection were calculated. The wind bodily form coefficients were gained. It was proved that the conclusion in this paper expresses the wind pressure distributingreally, by Comparing with the China national load standard. To reduce the suction and the press on the roof of the northern end-span was researched, a workroom was connected to the greenhouse at north. The wind pressure distributing on the surface of the NJ-6 type multi-span greenhouse and the workroom was numerical simulated again. The result shows that connecting workroom reduced the suction and the press on the roof of northern end-span 40 percent. The wind load on this place was reduced efficiently.The space cooperative performance of multi-span greenhouse was firstly studied in this paper. The theory to calculate the space cooperative performance in the course of multi-span greenhouse structural design was bring forward and researched. Properly predigesting the structure, importing the model of elastic foundation b...
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